Considering they are doing an Ant-Man film, I don't tihnk that is a fair argument.

They are, but that's not an ensemble like Avengers so they don't have to worry about all the other characters. Even saying that I have more concerns about Ant-Man than any other Marvel film, including Guardians of the Galaxy. We'll see.

Edit: Plus they could presumably simplify things in an Ant-Man solo. He doesn't need to fly around and fight a bunch of aliens/robots/alien-robots like he would in an Avengers film.